The present invention relates to a new and improved construction of winding device for automatically changing tubes for taking-up endless threads or the like.
Devices of this type are suitable in particular for use in spin-draw-winding during the manufacture of man-made fibers.
Winding devices for endless threads or the like are already known to the art wherein a tube placed upon a pivotably arranged bobbin chuck arm is pivoted into a winding position. Prior to contacting a friction drive drum which is provided for the purpose of driving the tube, the latter is accelerated by an accelerating ring provided at one end of the friction drive drum so as to possess a slightly higher rotational speed than the rotational speed prevailing during the winding operation. With this arrangement the accelerating ring is coaxially connected with the friction drive drum and its diameter is selected to be larger by a certain amount than that of the friction drive drum itself.
A drawback of such prior art winding device resides in the fact that the synchronous motor employed for driving the friction drive drum must be designed for winding the bobbin package and for the acceleration of the tube which is only required for a short period of time, in other words, must fulfill power requirements which are as much as four times greater than actually needed for merely driving the friction drive drum, in order to insure that the winding of the bobbin package, which is still in progress, while the next following empty tube is accelerated for the bobbin tube change operation, is not endangered by a reduction in the rotational speed or by a falling-out of step of the synchronous motor or the friction drive drum respectively.
A further disadvantage of the aforementioned state-of-the-art system resides in the fact that there is present a fixed difference between the circumferential speed of the accelerating ring and that of the friction drive drum. This drawback is manifested by virtue of the fact that there cannot be taken into consideration the differing thread take-up speeds generated by different thread traversing speeds at constant rotational speeds of the friction drive drum and the differing thread take-up tension at the bobbin tube change caused by virtue of the fact that the thread of necessity is not traversed during the times that there are formed the thread reserve windings. By changing the thread traversing speed with constant rotational speed it is possible to accommodate to the momentarily prevailing requirements the crossing angles of the threads or the like wound onto the bobbin package.